The new study, conducted at 50 U.S. medical centers, included 451 patients who suffered a stroke or mini-stroke caused by blockage of a major artery.

Patients treated at medical centers with more experience and expertise in aggressive treatment of stroke had lower rates of repeat stroke or death, according to the findings published in the Dec. 15 issue of the journal Neurology.

"We compared the rates of recurrent stroke or death for patients receiving aggressive medical management at the 12 centers with the highest study enrollment to those who received the treatment at the 38 with the lowest enrollment," said study leader Dr. David Chiu, a neurologist and medical director of the Houston Methodist Hospital Stroke Center.

"We found a significant difference in the rates after both 30 days -- 1.8 percent for the high-volume centers and 9.8 percent for the low-volume -- and after 2 years -- 7.3 percent versus 20.9 percent," he said in a hospital news release.

The researchers also found that patients treated at the high-volume centers had higher rates of excellent blood pressure and cholesterol control.

Other factors may affect stroke patients' outcomes, but this study strongly suggests that a medical center's expertise plays a major role, Chiu said.

"When we compared the frequencies of all known baseline characteristics and stroke risk factors, there were only a few differences between high-enrolling centers and low-enrolling centers but the only factor that explained the disparity in outcomes between the two groups was the center's experience," he said.

More information

The American Heart Association, American Stroke Association has more about stroke treatments.